and I solved it using Solve[] command, so I obtained 6 root objects.
Now I would like to evaluate these solutions for different ranges of the equation coefficients (a between a1 and a2, b between b1 and b2, etc), selecting the only one real positive solution (that always exists for each coefficient combination) within the six, and then use the Manipulate command in order to plot the surface corresponding to these real positive solutions as function ofthe other parameters.
Any help would be greatly appreciated.

Some notes:

I solved my Equation with this command line:

soldi = Solve[modqTomb - modqTomx == 0, di]

then I obtained my roots objects that are too long to post here.
I then tried to plot the solution selecting only the real positive one with this line

Hello Artes, thank you for your link. I also tried to list in a Table all my solution with the command line: grafico = Table[Evaluate[di /. soldi], {omegao, 50*2*Pi, 5000*2*Pi, 990*2*Pi}, {psiqgamma, 1*10^-1, 3.38*10^8, 6.7600*10^7}, {csik, 0.000001, 0.03, 0.0060}] and then extract with "case" and "select" commands the real and positive ones and I succeeded. But then I have a list ov values and I dont' know how to match them with the coordinates and use the manipulate
–
MartaJul 11 '13 at 18:13

@Marta To get help you expect you should edit your question including definitions of di, soldi, modqTomx, modqTomb etc. then it might be possible that one will be able to provide a full answer to your problem.
–
ArtesJul 11 '13 at 18:44

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